near-field communication (NFC)

What is near-field communication (NFC)?

Near-field communication (NFC) is a short-range wireless connectivity technology that uses magnetic field induction to enable communication between devices when they're touched together or brought within a few centimeters of each other. This includes authenticating credit cards, enabling physical access, transferring small files and jumpstarting more capable wireless links. Broadly speaking, it builds on and extends the work of existing ecosystems and standards around radio frequency ID tags (RFID).

NFC extends RFID and contactless capabilities with more dynamic features enabled by modern smartphones. All modern phones now support NFC chips and applications, such as Apple Pay and Google Pay, to take advantage of the billions of RFID tags and terminals already deployed. NFC makes it easier to load multiple cards into a single phone for payments, municipal transit, building access, opening car doors and other use cases. NFC supports interactive applications built on basic RFID capabilities such as automatically pairing Bluetooth headphones and Wi-Fi connections. It can also automatically pull up data or an app from a poster or ad.

It was originally intended to be used to transfer files between phones using Android Beam. Modern services, such as Google Nearby Share, employ NFC to configure wireless services across faster networks like Bluetooth or Wi-Fi direct.

NFC is limited to short-range communication, which has important implications for physical access security. A user must be within 3.5 inches (10 cm) of an NFC terminal to process a payment or open a door. Another important aspect is that no power is required for the basic mechanics of listening to and responding to NFC requests. This makes it possible to implement in items that lack a battery, such as credit cards.

NFC also complements wireless technologies such as Bluetooth, Ultrawideband (UWB), Wi-Fi direct and QR codes. Its most significant advantage is that it is the easiest wireless technology for setting up a connection, which makes it useful for IoT devices. However, it is not as good at maintaining a connection over distances or for long periods.

How does NFC work?

NFC works on top of three crucial innovations in wireless tag readers, cryptographic credit card processing and peer-to-peer (P2P) connectivity to enable various applications.

NFC builds on the work of the RFID set of standards and specifications, such as ISO/IEC 14443 and ISO/IEC 15963. These take advantage of a wireless communication technique using different physical principles than most wireless radios. Whereas most radios transmit data via radio wave propagation, NFC transmits data via magnetic field induction. NFC data transmits data at 13.56 MHz, which corresponds to a wavelength of 22 meters.

One critical aspect of transmitting data via induction coupling rather than radio waves is that the field fades out far more quickly than radio waves. This is useful for preventing people from listening in on sensitive conversations about credit card transactions, door access codes or other confidential information.

The second significant NFC innovation involves cryptographic credit card processing used for contactless payments. Public-key cryptography allows the card to generate a new authentication code for each transaction without revealing the raw card details or three-digit code on the back. This ensures that even if someone were to listen in or a hacker queried a card on a busy subway, they would never glean the original card details.

The NFC forum, a nonprofit industry association, took these two building blocks and added P2P connectivity on top of the ISO/IEC 18092 standard. Classic RFID and credit card use cases involve an active card reader that queries a passive tag or card, which is a one-way interaction. The NFC forum introduced specifications that allowed more capable devices like smartphones, headphones, routers, home appliances and industrial equipment to initiate or react to NFC queries. This opened a wide range of interaction and connectivity patterns. It also took a lot of work to simplify the exchange of information while minimizing security vulnerabilities. For example, you can tap two phones together to trade contact details using Android Beam but not accidentally swap executable code that may spread a virus.

Smartphone vendors are starting to build some basic application execution capabilities on top of this. In the Google ecosystem, a smart tag might launch a progressive web app running in the browser. Apple recently launched Apple App Clips, in which an NFC tag or QR code can launch apps with basic functionality for things like ordering in a restaurant or unlocking a rental scooter kiosk without downloading a full-blown app. These apps are limited from accessing sensitive data on the phone.

Examples of NFC

A few examples of NFC use cases include the following:

• mobile payments, such as Apple Pay and Google Pay;
• transit card payments;
• ticket redemption at a concert or theater;
• access authentication for doors or offices;
• unlocking car doors or rental scooters;
• venue or location check-in to alert friends on social media;
• device pairing smartphones and headsets by tapping them together;
• automatic setup for Wi-Fi connectivity by tapping a phone to a router or internet gateway;
• connection via smartphone to a radiator to configure its temperature settings and schedule; and
• connection via smartphone or tablet to industrial equipment to access a more complex control panel.

Benefits of NFC

NFC has several real-world benefits, including the following:

• increases operational efficiency for payment processors;
• ensures more security than traditional credit cards for payments;
• allows users to choose from multiple cards dynamically;
• difficult to intercept NFC communications from a distance;
• ease of use for consumers in paying for goods;
• simplifies access to back-end information; and
• allows simple setup of new connections compared to other wireless protocols.

Limitations of NFC

Challenges of NFC technology include the following:

• very short range of only a few inches precludes many use cases;
• slower than other protocols;
• can limit usability for apps that require sensitive data on a smartphone;
• app innovation stymied by Apple and Google restrictions and tech implementations;
• not suitable for location tracking; and
• not as universal and easy to integrate into venue ticketing apps as QR codes.

Differences between NFC and other wireless technologies

NFC complements a variety of other wireless technologies, including RFID, EMV (Europay, Mastercard and Visa), Bluetooth, UWB and QR codes. It also differs from these technologies in important ways.

NFC is best suited for authenticating transactions, unlocking doors and configuring other wireless connections. Other technologies work best in the following ways:

• RFID uses readers that can scan simple ID tags at long distances. Because it is unidirectional, this is best for reading toll tags, unlocking doors, authenticating passports or scanning inventory between more active readers and more passive tags.
• EMV allows for credit card transactions using a chip and an equipped payment terminal. While it also authenticates transactions, it is not as dynamic and interactive as NFC, which allows for contactless payments.
• Bluetooth offers a greater connection range than NFC but is less secure. It works best for connecting peripherals, such as headphones, to mobile devices and computers.
• UWB is a new technology and operates at a very low power using pulse patterns to keep from interfering with other wireless technologies. This allows it to send data quickly without losing accuracy. UWB excels in short-range location tracking, which works well for newer use cases, such as wireless car entry.
• QR codes need to be activated by the user by scanning an image with a smartphone's camera app, instead of a simple tap used by NFC. Businesses can easily generate QR codes for customers to retrieve promotions, product manuals or webpages from printed tags. QR codes are less complex and are easier to include in emails without having to rely on integration with Apple or Google specific functionality.

As far as detection range, NFC can only identify whether a device is next to another. Bluetooth can recognize when an object is within a room. UWB can locate a remote buried between couch cushions to within 10 cm. The Apple AirTag has all three kinds of radios to use a variety of patterns of connectivity, configuration, tracking and notification.